SQLCAT (Sharon Bjeletich) released a MS SQL Server 2005/2008 flowchart to troubleshoot performance issues in 2008.
The document is since long gone and there are lots of forum requests on the web, so I traced this little bugger down.
Altho, SQL Server 2005/2008 is a dead horse (or parrot) by now, but the flowchart could still be of some interest for those who are still forced to work with these by now unsupported versions or simply love flow charts like me.
I still haven’t found one for 2012/2014 sadly.
See Troubleshooting SQL for original PDF.